<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>


<script>

    //1.if
   /* var count = 3;
    if (count == 3) {
        alert(count);
    }*/

    //2.switch
   /* var num = 3;
    switch (count) {
        case 1:{
            alert("星期一");
            break;
        }

        case 2:{
            alert("星期二");
            break;
        }
        case 3:{
            alert("星期三");
            break;
        }
        case 4:{
            alert("星期四");
            break;
        }
        case 5:{
            alert("星期五");
            break;
        }
        case 6:{
            alert("星期六");
            break;
        }
        default:{
            alert("星期日")
            break;
        }
    }*/

    //3.for
    /*var sum = 0;
    for (let i = 0; i <= 100; i++) {
        sum += i;
    }
    alert(sum);*/


    //4.while
   /* var sum = 0;
    var i = 1;
    while (i <= 100){
        sum += i;
        i++;
    }
    alert(sum);*/

    //5.do...while
    var sum = 0;
    var i = 1;
    do {
        sum += i;
        i++;
    }while (i <= 100)
    alert(sum);

</script>
</body>
</html>